Methyl vinyl acetylene

The principal components of the cut are butene-1, butene-2, isobutylene and butadiene-1,3. Methyl, ethyl, and vinyl acetylenes, butane and butadiene-1,2 are present in small quantities. Butadiene is recovered from the C4 fraction by extraction with cuprous ammonium acetate (CAA) solution, or by extractive distillation with aqueous acetonitrile (ACN). The former process is a liquid-liquid separation, and the latter a vapor-liquid separation. Both take advantage of differences in structure and reactivity of the various C4 components to bring about the desired separation. 

A = Acrylonitrile B = Benzoquinone C = Naphthoquinone D = 5,8-Quinolinequinone E = Methyl vinyl ketone F = Dimethyl acetylene dicarboxylate G = Methyl acrylate ... 

METHYL ETHYL SULPHIDE N-PROPYL AMINE ISOPROPYL AMINE TRIMETHYL AMINE MALEIC ANHYDRIDE VINYL ACETYLENE... 

The catalytic system employing (2 - Fur)3P as ligand was applied to the coupling of methyl vinyl ketone and ethyl vinyl ketone to aromatic, aliphatic, acetylenic, and olefinic aldehydes (Scheme 23) [37]. Despite the hydrogenation conditions, alkyne and alkene moieties, as well as benzylic ether and nitro functional groups all remained intact. Furthermore, extremely high lev-... 

Methylene cyclopropene (5), the simplest triafulvene, is predicted to be of very low stability. From different MO calculations5 it has been estimated to possess only minor resonance stabilization ranging to 1 j3. Its high index of free valency4 at the exocyclic carbon atom causes an extreme tendency to polymerize, a process favored additionally by release of strain. Thus it is not surprising that only one attempt to prepare this elusive C4H4-hydrocarbon can be found in the literature. Photolysis and flash vacuum pyrolysis of cis-l-methylene-cyclopropene-2,3-dicarboxylic anhydride (58), however, did not yield methylene cyclopropene, but only vinyl acetylene as its (formal) product of isomerization in addition to small amounts of acetylene and methyl acetylene65 ... 

Although no reported work is available on vinyl acetylene oxidation, oxidation by O would probably lead primarily to the formation of CO, H2, and acetylene (via an intermediate methyl acetylene) [37], The oxidation of vinyl acetylene, or the cyclopentadienyl radical shown earlier, requires the formation of an adduct [as shown in reaction (3.142)]. When OH forms the adduct, the reaction is so exothermic that it drives the system back to the initial reacting species. Thus, O atoms become the primary oxidizing species in the reaction steps. This factor may explain why the fuel decay and intermediate species formed in rich and lean oxidation experiments follow the same trend, although rich experiments show much slower rates [65] because the concentrations of oxygen atoms are lower. Figure 3.13 is a summary of the reaction steps that form the general mechanism of benzene and the phenyl radical oxidation based on a modified version of a model proposed by Emdee et al. [61, 66], Other models of benzene oxidation [67, 68, which are based on Ref. [61], place emphasis on different reactions. 

KETENE, feef-butylcyano-, 55, 32 37, 38 Ketene 1 1-dimethylpropylcyano-, 55, 38 7-KETOESTERS, 58, 79, 81, 82 7-KETOESTERS TO PREPARE CYCLIC DIKETONES, 58, 83 KETONE terf-butyl phenyl, 55, 122 Ketone, methyl ethyl- 55, 25 Ketone, methyl vinyl, 56, 36 KETONES, acetylenic, 55, 52 Ketones, alkylation of, 56, 52 KETONFS aromatic, aromatic hydrocarbons from 55, 7... 

Fw and F0 are calculated by SCAP from group contributions. Four different contributions, called the hydration shell parameters, have to be considered for each group and each solvent. They have been listed for the methyl, methylene, methine, vinyl, acetylene, aromatic C, halogens (except I), and various O-, S-, and N-containing groups [64]. 

In the first route, methylbutenol is made from acetone and acetylene followed by hydrogenation. Reaction with methyl isopro-penyl ether yields methylheptenone (6). The second route involves the reaction of isobutylene, formaldehyde and acetone (7 ). Methyl vinyl ketone is an intermediate. Finally, methylheptenone is made by alkylation of acetone with prenyl chloride which is derived from isoprene (8). The initial product is the terminal olefin which is isomerized to the desired isopropylidene compound. 

Table 10.1 presents typical specifications for a polymerization-grade product, as well as some physical properties. Prohibited impurities refer to inhibitors (croton-aldehyde, vinyl acetylene), chain-transfer agents (acetic acid, acetaldehyde, acetone) and polymerizable species (vinyl crotonate), while methyl and ethyl acetate impurities are tolerated. 

Some alkynes undergo nucleophilic addition Thus acetylene adds methanol under pressure in the presence of sodium methoxide to form methyl vinyl ether (methoxyethene). 

CO, CHi. CO2, ethylene, acetylene, ethane. H2O. propylene, ethanal acetone, propanal, ethanol, benzene, toluene, ethylbenzene, styrene, p-vinyltoluene, benzaldehyde, p-ethyl-totuene acetophenone, methyl benzoate, vinyl benzoate, ethyl benzoate, p-methyl-acetophenone. benzoic acid, p-methyl vinyl benzoate, p-vinylacetophenone, propyl benzoate, p-ethyl vinyl benzoate, p-vinyl vinyl benzoate, biphenyl. 1-hydroxyethyl benzoate, diacetylbenzene. p-acetyl vinyl benzoate, divinyl terephthalate. ethyl vinyl terephthalate. ethyl vinyl terephthalate, p-acetyibenzoic acid, methyl 1-hydroxyethyl terephthalate. ethylene dibenzoate... 

CH5N 199 Methyl amine C4H4 339 Vinyl acetylene... 

Vitamin A synthesis. The addition of acetylene to methyl vinyl ketone is a key step in Isler s technical synthesis of vitamin A. The resulting carbinol (2) under... 

Aldol condensation of acetone with formaldehyde gives methyl vinyl ketone. This can undergo the ene reaction with isobutylene to give an isomer of methylheptenone, 2-methylhept-l-en-6-one. Isomerization to methylheptenone is easy using an acidic catalyst, and acetylene can be added to either isomer. From methylheptenone, the process leading to linalool is the same as in the examples above. If the acetylene is added to 2-methylhept-l-en-6-one, then isodehydrolinalool results. This is actually advantageous when the monoterpene unit is to be used as a precursor for ionones and vitamins, since the 1,1-disubstituted double bond is more reactive in the cyclization reaction than is the normal 1,1,2-trisubstituted bond. (The cyclization reaction is described in detail below.) The preparation of these two acetylenic ketones is shown in Scheme 4.9 and is the basis of a process commercialized by BASF. 

Acetylene hydration can also, be achieved by producing methyl vinyl ether as an intermediate, which is then hydrolysed to methanol and acetaldehyde. The following... 

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